Thyroid Hormone Action in Alzheimer's Disease and Related Dementias

Abstract: Thyroid hormone is among the most common prescriptions in the United States. Up to 20% of those on therapy are on doses which suppress the normal pituitary feedback system and result in a low thyrotropin (TSH) level, a sign of excess hormone. We have recently found that a low TSH is associated with an increased risk of a later diagnosis of cognitive disorder. This proposal aims to understand whether excess thyroid hormone is a preventable risk factor for Alzheimer's disease and related dementias. We will look at the relationship over time between thyroid hormone therapy, hormone levels, and dementia in several different large groups of patients. Our goals include identifying those who may be particularly vulnerable to excess thyroid hormone. This work is important because thyroid hormone is frequently prescribed to those with dementia and, with millions of older adults at risk, even simple changes to appropriately prescribe thyroid hormone could have important public health benefits.